An accelerometer is a sensor typically utilized for measuring acceleration forces. These forces may be static, like the constant force of gravity, or they can be dynamic, caused by moving or vibrating the accelerometer. An accelerometer may sense acceleration or other phenomena along one, two, or three axes or directions. From this information, the movement or orientation of the device in which the accelerometer is installed can be ascertained.
Accelerometers are used in inertial guidance systems, in airbag deployment systems in vehicles, and many other scientific and engineering systems. One growing use for micro electromechanical system (MEMS) accelerometers is in protection systems for a variety of devices. These protection systems ideally function to safeguard a device from shocks and vibration. Exemplary devices include camcorders, laptop and notebook computers, personal digital assistants (PDAs), cellular telephones, digital audio players, and other such devices that may include a built-in hard disk drive and/or comparable components. Free fall is the falling motion of a device subject to acceleration by gravity. Consequently, a free fall condition occurs when a device is dropped and damage can result when that device eventually strikes a surface. A protection system for safeguarding a device from damage that can occur when a device is dropped may include a MEMS accelerometer that senses a free fall condition. Upon sensing free fall, the protection system may cause power to the device to be automatically turned off and the writing head of the built-in hard disk drive may be disengaged so that a head crash can be avoided when the device strikes a surface.
In some instances, a manufacturer whose product includes a hard disk drive or other such device components may perform a drop test of their product. The drop test may entail dropping the finished product onto a surface to check the functionality of a free fall protection feature. The object of such testing is to ascertain detection of the free fall, and verify that the hard disk drive head and/or other device components are parked or otherwise disengaged upon detection of the free fall. Unfortunately, it can be difficult to conduct a controlled drop test. That is, there may be different results when the product is dropped from different heights, on different surfaces, and whether the product is simply dropped or thrown down. Moreover, such drop testing may scar, scratch, dent, or otherwise break the case of the finished product. Additionally, the drop test could break or shorten the lifespan of other components within the finished product. Accordingly, performing a drop test to ascertain the functionality of a free fall protection feature is difficult to control, time intensive, and costly in terms of damaged products.